We have analyzed the intracellular degradation of an immune complex after its FcgammaR-mediated uptake in antigen-presenting cells (APC). Mice that lack the cathepsins (Cat) S, L, B and D allowed us to assess the direct contribution of these individual proteases to the processing events observed. CatS and CatB mediate the bulk of degradation of the Ig-125I-labeled F(ab')2 immune complex delivered via FcgammaR, while CatL and CatD are dispensable. CatS and CatB are involved in independent… CONTINUE READING